To Florus 3.190

But afterward you introduce the statement dear to you: ‘If no evil were within human nature, it would not need to be saved. Whoever says it is not good denies a good Creator to the nature created; whoever denies it contains evil begrudges a merciful Savior to the nature corrupted’ (Augustine, Marriage and Sexual Desire 2.36). Let the reader pay attention: you will see that he has said nothing other than what he had denied should be said. You have pronounced evil naturally present in the very thing you said was not naturally evil.